Search results for "NICKEL"
showing 10 items of 1087 documents
The Crystal Structure of Nickel(II)-Azurin
1995
The nickel(II)-azurin metalloderivative has been crystallized and its structure solved at 0.205-nm resolution by X-ray diffraction. The overall structure is not modified by the metal exchange and the only differences with regard to the native copper(II)-azurin occur in the metal site region. These variations affect principally the axial ligands. Nickel co-ordinates more strongly to the carbonyl oxygen of Gly45 while its distance to the Met121 S4 enlarges up to 0.330 nm. The resulting metal center structure is intermediate between those of the Cu(II) and Zn(II) azurins, and can be described as distorted tetrahedral. However, the existence of contact interaction between Met121 and the nickel …
Apoferritin-encapsulated Ni and Co superparamagnetic nanoparticles
2006
Ni and Co nanoparticles (average diameters 3 and 3.5 nm) have been prepared within the apoferritin cavity. The protein shell prevents bulk aggregation of the metal particles, rendering them water soluble. X-Ray diffraction, transmission electronic microscopy and magnetization measurements have been used for characterizing the nanoparticles. The magnetic study of both nanoparticles confirmed the expected superparamagnetic behavior.
Template-based synthesis of nickel oxide
2015
Nanocrystalline NiO has been produced using a facile template-based synthesis from nickel nitrate solutions using cellulose as a template. Thus obtained oxides were studied by scanning electron microscopy, x-ray diffraction, Raman scattering spectroscopy, photoluminescence spectroscopy and confocal spectromicroscopy. The filamentary/coral morphology of the samples has been evidenced and is built up of agglomerated nanocrystallites with a size in the range of about 26-36 nm. The presence of two-magnon contribution in Raman scattering spectra suggests the existence of antiferromagnetic ordering at room temperature. Finally, the observed near-infrared photoluminescence band at 850 nm has been …
Synthesis, X‐ray Structure, Thermal and Magnetic Behavior of [(bipy) 2 Ni 2 (μ‐Cl) 2 Cl 2 (H 2 O) 2 ]: The First Neutral Ferromagnetically Coupled Si…
2007
NiCl2·6H2O and 2,2′-bipyridine (bipy) (1:1) were allowed to react under ambient conditions in dimethyl sulfoxide in the presence of acetylacetone (Hacac). The resulting green solution was concentrated in vacuo, and a green solid was isolated by precipitation with cold acetone. X-ray quality crystals of [(bipy)2Ni2(μ-Cl)2(Cl)2(H2O)2] (1) were grown by subsequent vapor/liquid diffusion of acetonitrile into a methanolic solution for one week. The structure of 1 consists of a dimeric nickel system with each metal atom in an octahedral geometry. Both equatorial bridging and axial chlorine atoms are present in this neutral species. The nickel–nickel distance (3.441 A) is the shortest reported to …
Versatile redox reactivity of triaryl-meso-substituted Ni(ii) porphyrin
2014
The electrochemical oxidation of nickel(II) 5,15-p-ditolyl-10-phenylporphyrin (1-Ni) leads to the formation of different coupling products, with the distribution depending on the nature of the solvent (CH2Cl2–CH3CN, CH2Cl2, DMF), the cell configuration (2 or 3 compartments) and the number of electrons abstracted. In a two compartment configuration (anode and cathode in the same compartment) in a CH2Cl2–CH3CN mixture, nickel(II) 5-chloro-10,20-p-ditolyl-15-phenylporphyrin (1-Ni-Cl) was isolated in good yield and its mechanism of formation is proposed. Switching to the three compartment configuration, the meso-β/meso-β doubly fused dimer (3-Ni) is detected as the major product whereas in pure…
Influence of Copper(II) and Nickel(II) Ions in the Topology of Systems Based on a Flexible Bis-Oxamate and Bipyridine Building Blocks
2014
Single crystals of the mononuclear bis-oxamate nickel(II) complex [Ni(bipy)(H2edpba)]·dmso (1) are obtained by reacting [Ni(bipy)Cl2]·H2O and the flexible K2(H2edpba) ligand [bipy = 2,2′-bipyridine; H4edpba = N,N′-2,2′-ethylenediphenylenebis(oxamic acid)]. The reaction of 1 with copper(II) ions resulted in two products in which the replacement of the nickel(II) ion by copper(II) took place: the chain compound [Cu(bipy)(H2edpba)]n·3nH2O·ndmso [dmso = dimethyl sulfoxide] (2) and the analogous chain compound without dmso crystallization molecules [Cu(bipy)(H2edpba)]n·1.5nH2O (3a) in its polycrystalline form. The reaction of [Cu(bipy)Cl2] and K2(H2edpba) yielded single crystals of [Cu(bipy)(H2e…
Synthesis of porous indium phosphide with nickel oxide crystallites on the surface
2022
Y. Suchikova, S. Kovachov, I. Bohdanov, І. Bardus show their appreciation to the Ministry of Education and Science of Ukraine for its support, in particular: grant 0122U000129 “Search for Optimal Conditions for the Synthesis of Nanostructures on the Surface of Semiconductors A3B5, A2B6 and Silicon for Photonics and Solar Energy,” and grant 0121U109426 “Theoretical and Methodological Principles of Systemic Fundamentalization of Intended Specialist Training in the Field of Nanophase Materials Science for Productive Professional Activity”.
Sustainable electroorganic synthesis of lignin-derived dicarboxylic acids
2020
The oxidative ring opening of lignin-derived alkylated cyclohexanols to bio-based alkylated dicarboxylic acids is successfully performed by an electrocatalytic conversion. To establish this transformation as a green method, we developed a simple protocol for the anodic oxidation at nickel oxide-hydroxide (NiOOH) foam anodes in caustic soda in both a batch and flow electrolysis approach.
About the selectivity and reactivity of active nickel electrodes in C–C coupling reactions
2020
Active anodes which are operating in highly stable protic media such as 1,1,1,3,3,3-hexafluoroisopropanol are rare. Nickel forms, within this unique solvent, a non-sacrificial active anode at constant current conditions, which is superior to the reported powerful molybdenum system. The reactivity for dehydrogenative coupling reactions of this novel active anode increases when the electrolyte is not stirred during electrolysis. Besides the aryl-aryl coupling, a dehydrogenative arylation reaction of benzylic nitriles was found while stirring the mixture providing quick access to synthetically useful building blocks.
Electrochemistry as an Attractive and Effective Tool for the Synthesis and Immobilization of Porphyrins on an Electrode Surface
2014
Magnesium(II) 10-phenyl-5,15-p-ditolylporphyrin is easily and cleanly transformed by electrolysis. A nitro group is first introduced at the free meso position by anodic substitution. Hydrogenation into the amine is then carried out electrocatalytically under ambient conditions with water as a hydrogen supplier. The synthesized porphyrin under the nickel(II) form can be covalently grafted onto a platinum electrode by electrochemical reduction of the diazonium cation, generated in situ by a reaction of the nickel(II) aminoporphyrin with sodium nitrite and trifluoroacetic acid. The electrosynthesized thin film gives an electrochemical response typical of a porphyrin material. Films grown under…